1.21.1 Port - Major fixes and improvements

Biome Generation:

• Fixed biome distance-from-spawn check using biome CENTER position instead of sampling position
• Added config version system (v3) that auto-deletes old configs when version changes
• 4/6 biomes working: Magnetic Caves, Primordial Caves, Toxic Caves, Candy Cavity
• Forlorn Hollows and Abyssal Chasm still need work (known issue)
• Added /locateacbiome command for debugging biome generation

Items & Equipment:

• Fixed Darkness Armor meter/ability not working (merged charging logic into inventoryTick)
• Fixed Seeking Arrow not firing from Dreadbow (updated createArrow signature for 1.21)
• Fixed Burrowing Arrow createArrow signature for 1.21 compatibility
• Fixed custom Rarity enum issue - using standard Rarity values as placeholders

Entities:

• Fixed Submarine camera position being too high (corrected positionRider calculation)

Tags:

• Added missing neoforge:storage_blocks/uranium tag
• Added missing neoforge:storage_blocks/gold tag
• Added missing neoforge:nuggets/iron tag
• Added missing neoforge:raw_materials/iron tag
• Added missing neoforge:gravel tag

Cleanup:

• Removed excessive logging from ACBiomeMapHolder and BiomeSourceMixin